The Biostatistics Core will promote the goals of the MADRC and serve the needs of individual projects by providing centralized management of clinical and research data and statistical expertise in experimental design and data analysis. The Core will maintain a relational multi-user database for the MADRC consisting of: (a) a registry of normals and patients evaluated by teh Clinical Core, together with an indication of their appropriateness for clinical studies; and (b) extensive clinical and research data on the subset of patients in (a) who are participating in research studies or who are being followed longitudinally throughout the course of their illness. The database also will include data on patients whose brain tissue is stored in the Neuropathology Core. The Biostatistics Core will facilitate the ongoing collaborative research of the MADRC by integrating the data from research studies, cores and satellites into this single database. The accuracy and completeness of the data will be assured by the use of established procedures for data entry, validation and verification. Interactive access to the database will be provided to personnel in other MADRC cores and projects under guidelines established to maintain patient confidentiality and the integrity of individual investigators' data. Core personnel will provide training to investigators in the use of this database to access individual records and generate patient lists. The Biostatistics Core will collaborate with MADRC investigators in the design of their research studies on dementia-related topics prior to their submission to the MADRC and funding agencies. Core personnel will assist project investigators in the completion of statistical analyses of their data by providing advice and training to MADRC-affiliated investigators in routine data analysis, and when indicated, carry out more complex statistical analyses for project investigators.